Using a newly developed system for measuring the electromagnetic (EM) environment in the earth, we detected electric pulses originating from the ground. The intensity of the electric pulses detected above the ground was weaker than those in the earth. There were clear lower frequency cutoffs in the spectra suggesting the existence of a kind of horizontal wave-guide in the earth and the propagation of EM waves there. The estimated scale depth of the bottom conductive boundary of the wave-guide is consistent with the result obtained from geomagnetic field investigations. The detected electric pulse swarms provided important images of EM wave behavior in the earth.